Preliminary Results on the Influence of Carbonic Snow Addition during the Olive Processing: Oil Extraction Yield and Elemental Profile

Abstract

The compositional profile of olive oil is strictly connected to the raw material characteristics, nevertheless technological processes utilized to extract the oil fraction can deeply impact on its final chemical composition. Trace quantities of elements are naturally present in olive oil. To make objective and measurable food quality and traceability, it is necessary to develop analytical methods useful to detect contaminants potentially coming from any phases of the supply chain and define characteristic markers and patterns for the authenticity verification and origin demonstration. The objective of the paper is twofold: a) to verify the influence of the addition of cryogen (CO2,s), directly to olives during pre-milling phase, on the yield of the oil production; b) to develop specific analytical methods for evaluating the elemental profile of olive oil and to collect some preliminary data about the possibility to use these methods in order to put in evidence the possible influence of different process conditions on the olive oil elemental profile. The experimental evidences show as the addition of cryogen directly to the olives during pre-milling phase seem induce a general increase in the oil extraction yield, ranging from 2 to 12,4%. While preliminary results show a rather homogeneous elemental content among all the analyzed samples of olive oil, samples of olive oil obtained by the “traditional” process showed - in general - a higher content of Ca, Cr, Mg, Si and Zn, compared to those obtained by the addition of “carbonic snow”. The analytical methods for evaluating the olive oil elemental profile by ICP-AES and ICP-MS were set up and the methodologies for data processing and statistical analysis were developed, so they could be applied during the next crop season to study in depth the influence of different process conditions on the olive oil elemental profile.